Abstract
The contribution of α-adrenoceptors and nitric oxide (NO) on the alterations of sympathetically mediated cardiovascular responses after acute (AcH) and chronic (ChH) hypertension was evaluated in pithed aortic coarcted hypertensive rats. Pressor and tachycardia response produced by electrical stimulation of preganglionic sympathetic fibers or exogenous noradrenaline (NA) were recorded in the absence and presence of prazosin (α1-antagonist), rauwolscine (α2-antagonist), or N G-nitro-l-arginine methyl ester (l-NAME; an inhibitor of NO synthase). Compared with age-matched sham-operated rats (Nt), the pressor response produced by electrical stimulation or NA was smaller in AcH rats and larger in ChH rats. Prazosin caused a decrease of pressor response elicited by electrical stimulation or NA in all groups. However, this effect was higher in ChH. Rauwolscine produced a similar increase of sympathetically mediated pressor response in Nt and AcH rats. Nevertheless, this antagonist did not affect the sympathetically mediated pressor response in ChH rats. In addition, rauwolscine did not affect the NA-induced pressor response in all groups. The pressor response elicited by l-NAME was larger in all groups compared without l-NAME and in presence of l-arginine. Moreover, l-NAME in the presence of NA increased sympathetically mediated pressor response is in all groups, compared without it or in the presence of l-arginine. Compared with Nt, basally produced NO in aortic rings was increased in AcH but decreased in ChH. Collectively, our data suggest that decreased cardiovascular reactivity in AcH is due to an increase in basally produced NO. In ChH, enhanced cardiovascular response appears to be associated with a decrease in produced NO and an increase in released NA from sympathetic nerves.
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References
Barton CH, Ni Z, Vaziri ND (2001) Enhanced nitric oxide inactivation in aortic coarctation-induced hypertension. Kidney Int 60:1083–1087
Beznák M (1956) Hemodynamic changes following aortic constriction in normal and in hypophysectomized rats. Can J Biochem Physol 34:791–798
Bucher B, Ouedraogo S, Tschopl M, Paya D, Stocket JC (1992) Role of the L-arginine-NO pathway and of cyclic GMP in electrical field-induced noradrenaline release and vasoconstriction in the rat tail artery. Br J Pharmacol 107:976–982
Cordellini S, Novo R, Júnior UL (2006) Exposure to stress: differential vascular adaptive response in spontaneously hypertensive and Wistar rats: role of nitric oxide, and prehypertensive and hypertensive states. Life Sci 79:646–653
Damase-Michel C, Tran MA, Llau ME, Chollet F, Senard JM, Guiraud-Chaumeil B et al (1993) The effect of yohimbine on sympathetic responsiveness in essential hypertension. Eur J Clin Pharmacol 44:199–201
de Champlain J (1990) Pre- and postsynaptic adrenergic dysfunctions in hypertension. J Hypertens Suppl 8:S77–S85
Egan B (1992) Vascular reactivity, sympathetic tone, and stress. In: Johnson E, Gentry W, Julius S (eds) Personality, elevated blood pressure and essential hypertension. Hemisphere, Washington, DC
Egi Y, Matsumura Y, Murata S, Umekawa T, Hisaki K, Takaoka M et al (1994) The effects of N-G-nitro-L-arginine, a nitric oxide synthase inhibitor, on norepinephrine overflow and antidiuresis induced by stimulation of renal nerves in anesthetized dog. J Pharmacol Exp Ther 269:529–535
Gillespie JS, Muir TC (1967) A method of stimulating the complete sympathetic outflow from the spinal cord to blood vessels in the pithed rat. Brit J Pharmac Chemother 30:78–87
Green LC, Tannenbaum SR, Goldman P (1981) Nitrate synthesis in the germfree and conventional rat. Science 212:56–58
Greenberg SS, Diecke FP, Peevy K, Tanaka TP (1989) The endothelium modulates adrenergic neurotransmission to canine pulmonary arteries and veins. Eur J Pharmacol 162:67–80
Hatanaka Y, Hobara N, Honghua J, Akiyama S, Nawa H, Kobayashi Y, Takayama F, Gomita Y, Kawasaki H (2006) Neuronal nitric-oxide synthase inhibition facilitates adrenergic neurotransmission in rat mesenteric resistance arteries. J Pharmacol Exp Ther 316:490–497
Jonsson JR, Head RJ, Frewin DB (1992) Effect of alpha 1-adrenoceptor blockade on the development of hypertension in the spontaneously hypertensive rat. Eur J Pharmacol 211:263–268
Julius S, Majahalme S (2000) The changing face of sympathetic overactivity in hypertension. Ann Med 32:365–370
Julius S, Nesbitt S (1996) Sympathetic overactivity in hypertension. A moving target. Am J Hypertens 9:113S–120S
Miyajima E, Yamada Y, Yoshida Y, Matsukawa T, Shinoiri H, Tochikubo O et al (1991) Muscle sympathetic nerve activity in renovascular hypertension and primary aldosteronism. Hypertension 17:1057–1062
Ruffolo RR, Nichols AJ, Stadel JM, Hieble JP (1993) Pharmacologic and therapeutic applications of alpha-2 adrenoceptor subtypes. Annu Rev Pharmacol Toxicol 32:243–279
Sessa WC, Pritchard K, Seyedi N, Wang J, Hintze TH (1994) Chronic exercise in dogs increases coronary vascular nitric oxide production and endothelial cell nitric oxide synthase gene expression. Circ Res 74:349–353
Shipley RE, Tilden JH (1947) A pithed rat preparation suitable for assaying pressor substances. Proc Soc Exp Biol Med 64:453–455
Shultz PJ, Raij L (1992) Endogenously synthesized nitric oxide prevents endotoxin-induced glomerular thrombosis. J Clin Invest 90:1718–1725
Sindhu RK, Roberts CK, Ehdaie Z, Zhan CD, Vaziri ND (2005) Effects of aortic coarctation on aortic antioxidant enzymes and NADPH oxidase protein expression. Life Sci 76(8):945–953
Starke K (1987) Presynaptic alpha-autoreceptors. Rev Physiol Biochem Pharmacol 107:73–146
Tsuda K, Kimura K, Shima H, Nishio I, Masuyama Y (1992) Presynaptic alpha 2-adrenoceptor-mediated modulation of norepinephrine release from vascular adrenergic neurons in reduced mass SALT hypertensive rats. Clin Exp Pharmacol Physiol 19:531–535
Versari D, Daghini E, Virdis A, Ghiadoni L, Taddei S (2009) Endothelium-dependent contractions and endothelial dysfunction in human hypertension. Br J Pharmacol 157:527–536
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Hong, E., Larios, F., Gómez-Viquez, N.L. et al. Role of alpha adrenoceptors and nitric oxide on cardiovascular responses in acute and chronic hypertension. J Physiol Biochem 67, 427–435 (2011). https://doi.org/10.1007/s13105-011-0093-3
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DOI: https://doi.org/10.1007/s13105-011-0093-3